PTAB

IPR2021-01441

Amperex Technology Ltd v. Maxell Ltd

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1. Case Identification

2. Patent Overview

  • Title: Nonaqueous Secondary Battery
  • Brief Description: The ’035 patent discloses a nonaqueous secondary battery with a positive electrode active material that includes at least two distinct lithium-containing transition metal oxides having different average particle sizes to improve battery performance.

3. Grounds for Unpatentability

Ground 1: Obviousness over Choi and Noh - Claims 1-11 are obvious over Choi in view of Noh.

  • Prior Art Relied Upon: Choi (Application # US2006/0257745) and Noh (Application # US2004/0197667).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Choi taught all elements of claim 1 except for a fluorine-containing organic solvent in the electrolyte. Choi disclosed a lithium secondary battery using a positive electrode with at least two active materials of different average particle sizes (a large diameter material and a small diameter material) to improve packing density. Choi further disclosed specific compositional formulas for these materials that Petitioner mapped to the formulas required by claim 1, including the presence of elements like Co, Mg, and Al. Petitioner asserted that Choi's disclosed ranges for elemental concentrations and particle sizes overlap with and render obvious the ranges recited in the challenged claims.
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would combine Noh’s teachings with Choi’s battery. Choi stated a goal of improving thermal stability. Noh taught that adding a fluorine-containing carbonate-based additive to a similar battery’s electrolyte expressly improved thermal stability and discharge characteristics. A POSITA would have therefore been motivated to incorporate Noh’s fluorine-containing additive into Choi’s electrolyte via simple substitution to achieve this known benefit in a predictable manner.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because the battery systems in Choi and Noh used similar cathode, anode, and electrolyte materials. The predictable nature of lithium-ion chemistry and Noh's explicit disclosure of improved thermal stability would confirm the expected outcome.

Ground 2: Obviousness over Negishi and Kita - Claims 1-6 and 9-11 are obvious over Negishi in view of Kita.

  • Prior Art Relied Upon: Negishi (JP2000082466) and Kita (JP2002270238).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Negishi, like Choi, disclosed the core features of a nonaqueous secondary battery with a cathode containing two or more types of lithium complex oxide particles with different average particle sizes. Negishi provided compositional formulas and elemental ranges for its cathode materials that Petitioner argued meet the limitations of claim 1. However, Negishi did not explicitly teach the use of a fluorine-containing organic solvent in its electrolyte.
    • Motivation to Combine: The primary motivation was to improve battery capacity, a stated goal of Negishi. Kita taught that including an organic fluorine-based solvent in the electrolyte forms a protective film on the positive electrode surface during charging. This film was disclosed to protect the cathode material at the high voltages needed to increase capacity. As both references addressed improving performance in similar battery types, a POSITA would have been motivated to add Kita’s protective electrolyte solvent to Negishi’s battery to improve its capacity and high-voltage performance.
    • Expectation of Success: Petitioner argued for a high expectation of success because both references used similar materials (lithium complex metal oxide cathodes, graphite anodes) and sought to improve battery capacity. Kita demonstrated that its fluorine-containing additive was effective in such systems, making the outcome of the combination predictable.
  • Additional Grounds: Petitioner asserted obviousness challenges for claim 8 over Negishi, Kita, and Ishikawa, and for claim 7 over Negishi, Kita, and Awano. These grounds added teachings for a fluorine-containing aromatic compound (Ishikawa) and specific electrode density ranges (Awano) to the core combination of Negishi and Kita.

4. Key Technical Contentions (Beyond Claim Construction)

  • Petitioner argued for a narrow interpretation of the claim term "at least two lithium-containing transition metal oxides." It contended this requires a mixture of two chemically distinct and separate lithium-containing transition metal oxides, as opposed to a broader interpretation that might encompass multiple particle sizes of a single type of oxide.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under §314(a) based on the Fintiv factors would be inappropriate. The petition asserted that co-pending district court litigation was in its infancy, with jurisdictional disputes unresolved and no substantive investment in validity issues. Specifically, Petitioner argued:
    • Trial Date Proximity: No trial date had been set in one pending case, and a tentative date in another was likely to be postponed pending resolution of dispositive motions. The proximity of a trial date was therefore not a dispositive factor against institution.
    • Investment in Litigation: Investment in the district court proceedings had been minimal, focusing only on preliminary jurisdictional and venue issues. No significant discovery or claim construction had occurred, meaning there was little risk of duplicative efforts or inefficient use of resources.
  • Petitioner also argued that denial under §325(d) was improper because the primary prior art references and arguments presented in the petition were not previously considered by the USPTO during prosecution.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-11 of Patent 9,077,035 as unpatentable.